I have some questions about the boundary layer cells thickness for the S-A model.

1.. I understand that in order to get better results by using S-A model without wall function you need to make yPlus in the range of order 1. I wonder how the results will be if I use a much finer bundary layer grids , like yPlus in the order of 0.001? Is it just a waste of time without any improvement of the results or it will yield a worse one.

2.. how many cells in the boundary layer in the direction normal to the wall is a good choice, any guidelines?

3..if I use the boundary layer cells which have high aspect ratio like over 100, will that affect the accuracy a lot?